Laser delivery system for eye surgery

ABSTRACT

A photodisruptive laser delivery system and method for use in eye surgery. The photo disruptive laser delivered in pulses in the range of &lt;10000 femtoseconds, used to create incisions in eye tissue is delivered by novel means to minimize optical aberrations without the use of a complex system of multiply precisely arranged lenses. This novel means include a scanning design that allows the focusing lens to always remain under normal incidence to the photodisruptive laser beam, negating the need for overly complex aberration correction set up. The focusing lens is configured to move within a surrounding beam to facilitate two dimensional controls over the treatment space. Controlling beam divergence prior to focusing allows for 3D incisions. The system and methods of use accomplish precise treatment without the need to contact the patient and can be integrated into standard surgical microscopes to improve operational efficiency and hospital workflow.

CROSS-REFERENCE

The present application is a non-provisional of, and claims the benefitof priority under 35 U.S.C. §119(e) of U.S. Provisional Application No.61/495,370 filed Jun. 9, 2011, the entire contents of which areincorporated herein by reference.

The present application is related to the following co-pending patentapplication U.S. 61/619,386 the entire contents of which areincorporated herein by reference. The pending application is alsorelated to U.S. patent application Ser. No. 12/902,105 andPCT/US11/54506.

BACKGROUND OF THE INVENTION

The present invention generally relates to systems, apparatus, andmethods related to eye surgery. More particularly, the present inventionrelates to systems, apparatus and methods for cataract surgery. Cataractsurgery is one of the most common ophthalmic surgical proceduresperformed. The primary goal of cataract surgery is the removal of thedefective lens and replacement with an artificial lens or intraocularlens (IOL) that restores some of the optical properties of the defectivelens.

The major steps in cataract surgery consist of making cornea incisionsto allow access to the anterior chamber of the eye and to correct forastigmatism (Limbal relaxing incisions, LRIs), cutting and opening thecapsule of the lens to gain access to the lens, fragmenting and removingof the lens and in most cases placing an artificial intraocular lens inthe eye.

The cornea incisions are typically performed with surgical knives ormore recently with lasers.

Cutting of the capsule is most commonly done through skillful mechanicalcutting and tearing a circle shaped opening, using hand tools. Thisprocedure is called capsulorhexis.

Traditional methods for performing a capsulorhexis are based onmechanical cut and peeling techniques. Another method referred to as YAGlaser anterior capsulotomy delivers individual laser pulses with highenergy to the eye to assist with the opening of the capsule. Theprecision and quality of these methods is limited.

More recently, photodisruptive lasers and methods have been introducedthat can perform the capsulotomy/capsulorhexis opening cut with greatprecision. The inventor's prior patents and patent applicationsregarding photodisruptive lasers for use in eye surgery include: U.S.Pat. No. 6,992,765, U.S. Pat. No. 7,371,230,U.S. 61/619,U.S. Ser. No.12/902,105, and PCT/US11/54506. Photodisruptive laser pulses in therange of <10000 femtoseconds have been successfully applied to makeincisions into various tissues of the eye. The main focus to date hasbeen using a femtosecond laser for various cornea incisions such asLASIK flaps, intrastromal incisions, Limbal Relaxing Incisions,Keratoplasties and cornea entry incisions. In more recent yearsfemtosecond lasers have also been successfully applied to the capsuleand the lens of the human eye in femtosecond laser assisted cataractprocedures.

The main benefit of these photodisruptive laser pulses lays in the factthat the eye tissues that are treated transmit the wavelengths of thetypically chosen lasers, usually in the near infrared or visible rangeand therefore allow the laser to be focused through the cornea, aqueoushumor, lens capsule and lens without much scattering or absorption. Thelaser pulses are always focused to a very small spot size in the rangeof a few micrometers, so that a laser induced optical breakdown isachieved in any tissue or liquid (e.g. aqueous humor) that falls withinthe spot size location.

This optical breakdown (photodisruptive breakdown) creates a microplasma followed by a small cavitation bubble. This photodisruption oftissue can be used to cut and dissect tissue areas of any size andshapes by scanning a sequence of many such laser pulses over a desiredvolume in the eye.

Since the tissue layers in the laser path above and below the focuspoint are below the optical breakdown threshold and since they don'tsignificantly absorb the laser wavelength, they remain unaffected by thelaser beam. This principle allows non-invasive photo disruptive eyesurgery since no incision from the outside needs to be made.

There is a threshold of a minimum laser fluence (laser peak powerdivided by focus area) required to achieve the optical breakdown. Thelaser peak power goes up with higher pulse energy (typically in the μJrange) and shorter pulse duration (typically <600 fs). The laser fluencefor any given peak power goes up as the focus area goes down. Achievinga small spot size is therefore critical in achieving a high fluence thatexceeds the optical breakdown threshold.

The way of achieving a high enough fluence for breakdown by increasingthe laser pulse energy is less desirable since a higher pulse energycomes with a larger cavitation bubble and associated shock wave. Thelarger the cavitation bubble the less precision is achieved in cuttingany features with a sequence of pulses. Furthermore a large shock waveis considered a undesired side effect since it has the potential todamage surrounding tissues.

Priority is therefore given to minimizing the spot size to achieve anabove threshold laser fluence while using laser pulses within a lowpulse energy range of typically <50 μJ per laser pulse. These principleshave been successfully implemented in femtosecond eye laser systemstreating the cornea or capsule/lens of an eye. Typical laser beamfocusing convergence angles required are numerical apertures of NA>0.15(full angle Φ>15 deg) and in some optimized cases NA>0.3.

According to:

ω₀ =M ²360λ/π²Θ  Formula 1

Φ=full focusing convergence angle in degrees

λ=laser wavelength

ω₀=laser beam focus radius defined by 1/e² cut off

M²=beam quality factor determined by the total aberrations

If beam aberrations can be kept to a minimum e.g. M²<1.3 (M²=1 is thetheoretical minimum with no aberration at all) then the above focusingangles of NA>0.15 (Φ>15 deg) and NA>0.30 (Φ>30 deg) the resulting spotsize diameters (2ω₀) will be <8 μm and <4 μm respectively (for a laserwavelength λ=1 μm).

The high numerical aperture and minimization of aberrations is criticalin achieving such small spot sizes. The laser delivery systems for suchlaser parameters face several challenges due to the high numericalaperture required for to achieve a very small spot size. These systemsget further complicated by using a laser beam that is scanned throughthe focusing lens assembly. Maintaining low aberration while scanning alaser beam at an incidence angle other than normal (90 degrees ofincidence) through a lens that creates a high numerical aperture focusedbeam, requires a complex system of multiple lenses in a precisearrangement. Additionally, those methods and systems require a patientinterface such as an applanation lens to reference and fixate the eye tothe laser system. Placement of this patient interface adds significantcomplexity to the surgical setup and can cause undesired or harmful highintraocular pressures levels for the duration of the laser procedure.The patient interface is typically provided sterile and is used onlyonce therefore adding significant cost to the overall cataractprocedure. Additionally, No current patient interface or laser deliverysystem that can perform the laser cornea incisions and laser capsulotomyis compatible or has been integrated with a standard surgicalmicroscope. Since the cataract surgery requires a surgical operatingmicroscope to be completed, the patient must be moved and repositionedunder a surgical microscope after the current laser assisted parts ofthe procedure have been completed. This causes a significant time delayand logistical effort.

The delivery system, disclosed herein, avoids such a complex focusinglens setup by implementing a specific laser scanning design that allowsthe focusing lens to always remain under normal incidence (90 degrees)to the incoming laser beam(s). This dramatically reduces the deliverysystem size, complexity and induced beam aberrations. Furthermore,several novel delivery system integration designs are disclosed thatallow a femtosecond laser treatment with or without a patient interfaceto be integrated with a standard surgical microscope. This applicationdescribes, among others, techniques, methods, apparatus and systems forlaser based cornea incisions and capsule perforations (capsulotomy) tocreate an easier capsulorhexis procedure. Implementation of thedescribed techniques, apparatus and systems include: determining asurgical target region in the cornea and anterior capsule of the eye,and applying laser pulses to photo disrupt a portion of the determinedtarget region to create an opening cut on a cornea or capsule of thelens.

SUMMARY OF THE INVENTION

This application relates to techniques, apparatus and systems for lasereye surgery or laser assisted eye surgery.

This invention describes a specific laser delivery system design thatcan be used for various surgical procedures in the eye. It also includesnovel contact lens (patient interface) designs, that work together withthe different delivery system versions here presented. Its preferredembodiment is the delivery of a sequence of ultra short (<50000femtosecond from now on referred here as fs=femtosecond) laser pulses toachieve an optical breakdown inside the eye tissue at a small spot size(typically <10 micrometer in diameter). The sequence of laser pulses canbe used to photo disrupt or cut a specific tissue part inside or on thesurface of the eye. This delivery system scans the pulses in varyingcircular patterns achieving a combination of full and partical circularcut patterns at varying depth of the cut plane. The invention includesspecific methods and designs to control and minimize laser beamwavefront abberations, so that a very small focusing spot size can beachieved even without a hard connection between the eye (with or withouta contact lens) and the delivery system optics.

A novel aspect of the various embodiments of the invention includes theuse of a scanning system, that leaves the focusing lens (assembly)always under a normal (90 degrees) optical incidence angle and thereforedramatically minimizes optical aberrations, that normally requirecomplex optical lens systems to compensate. This design approach allowsfor the use of a very simple and small main focusing lens (assembly).The various embodiments of the invention allow for no contact betweenthe laser delivery system and the eye.

Some embodiments of the invention comprise a method for forming anincision in eye tissue. The said method comprising: directing afemtosecond laser beam in an axial direction, moving a lens, over a pathwithin the beam, wherein a plane of the lens remains perpendicular tothe axial direction and the lens focuses an incident portion of thelaser beam to a spot within the eye tissue. The spot has a size whichwill photo-disrupt tissue along a two dimensional path determined by thepath of the lens. Some embodiments further comprise the step ofcontrolling exapansion of the femtosecond laser beam and comprise theapparatus required to adjust beam expansion. Such apparatus or meansinclude beam expanders and Galileo lenses or other means well known inthe art.

The above and other embodiments of the invention may further comprisethe step of controlling a depth of focus of the laser spot to create athree dimensional treatment area within the eye tissue. One method ofcontrolling the depth of focus of the laser spot applicable to anytypical embodiment of the invention comprises the step of moving thefocusing lens in its mounting back and forward along the axialdirection. Another method of controlling the depth of focus of the laserspot applicable to any typical embodiment of the invention comprises thestep of adjusting the collimation angle of the beam after it exits abeam expander and prior to the beam striking the lens. This collimationangle is referred to herein as the exit expansion. The beam expander,described above, may be used to accomplish this task. Adjusting the exitexpansion of the beam, as herein described, means increasing ordecreasing the divergence of the femtosecond laser beam. Adjusting theexpansion exit of the beam may be accomplished by various methods suchas controlling the distance between a pair of lenses in a Galileotelescope or adjustment by a beam expander. Typically, the lens is movedover a circular path to create a cylindrical incision in the eye tissue.Other lens path geometries may be used to create various incisionpatterns in the eye tissue. Additionally, in any aspect of the inventiondescribed herein, the lens may be rotated about its own axis in additionto being moved over a path within the beam. Such rotation may be usefulwhen compensating for aberration. Additionally, some embodiments of theinvention further include measures to block portions of the femtosecondlaser beam which are not incident on the lens.

The invention may be applied to any eye tissue. Typically in the case ofperforming a capsulorexis or capsulotomy the eye tissue comprises a lenscapsule. However, in other uses the eye tissue may include but is notlimited to the lens, cornea, vitrious, retina, and anterior chamber.

In preferred embodiments of the invention moving the lens comprisesrotating a lens support about an axis parallel to the axial direction ofthe beam axis, wherein a center of the lens is radially offset from thesupport axis. The lens support may comprise an opaque material for thepurposes of blocking the laser beam. Typically, the lens is an opaquedisc which allows the laser beam to pass only through the lens. The lenssupport may be rotated at a rate in the range from 1 rotation per secondto 100 rotations per second. This aspect and any aspect of the inventionusing a lens support may further comprise adjusting the radial offsetbetween the center of the lens and support axis.

In some embodiments the invention further comprises aiming the lensprior to directing the femtosecond laser beam through the lens. Aimingthe lens may comprise directing a low power light through the movinglens so that a visible pattern is projected on the tissue, wherein theorientation of the lens can be adjusted until the visible pattern islocated at a desired incision site. Additionally, some embodimentsfurther comprise deflecting the focused beam from the moving lens tofollow a path at an angle relative to the axial direction. Deflectingthe focused beam typically comprises, but is not limited to, placing apartially reflective mirror in the focused beam to allow viewing of theeye tissue through the mirror. Such a mirror may be at 45° relative tothe axial direction.

In some embodiments this 45° mirror becomes a two axis scanning mirrorthat increases the 3 dimensional scanning ability of the deliverysystem.

Another aspect of the present invention is a system for performingpartial circular treatment patterns by modulating the laser beam on andoff during certain segments of the full circular lens rotation. Theon-off modulation is preferably achieved with a mechanical laser shutteror electro-optical modulation of the laser beam at the laser enginemodule.

Another aspect of the present invention is a system for forming a threedimensional incision into eye tissue. In a preferred embodiment thesystem comprises: a femtosecond laser source which directs a beam in anaxial direction, a focusing lens, a lens support which holds thefocusing lens in a plane perpendicular to the axial direction and whichmoves the lens over a two dimensional path in the perpendicular plane.The focusing lens focuses a portion of the beam incident on the lens toa spot size selected to disrupt eye tissue. This preferred embodimentalso has means for controlling the depth of focus of the laser spot tocreate a three dimensional incision within the eye. The laser source ofthe preferred embodiment comprises a laser which produces a collimatedfemtosecond laser beam; and means for expanding the beam prior to thebeam reaching the focusing lens. The means for expanding the beam maycomprise a Galileo telescope with a fixed expansion factor. Such meansmay alternatively or additionally comprise a zoom expander that allowsadjustment of the beam expansion factor. This allows for easy adjustmentfrom overfilling the lens to various degrees of under filling the lensand thereby changing the delivered laser power and numerical aperture ofthe focused beam resulting in a variation of spot size. As with previousembodiments, adjusting the exit expansion means adjusting (increasing ordecreasing) the divergence of the femtosecond laser. As described inabove embodiments the means of expanding the beam exit prior the beamreaching the focusing lens may comprise an adjustable Galileo telescope.Such means may alternatively or additionally comprise an adjustable zoombeam expander. The means of adjusting the exit expansion of the beam isadjustable to control the depth of focus of the laser spot with the eyetissue.

In some embodiments, the focusing lens is a single plano-convex oraspherical lens and the lens support is mounted to rotate about an axisparallel to the axial direction and wherein a center of the lens isradially offset from the axis. Furthermore in some embodiments thefocusing lens a single aspherical lens that pre compensates beamaberrations that the laser beam experiences as it propagates into theeye. For instance, if characteristic aberrations of a patient's eye arewell known or measured, then a custom focusing lens may be ground tocompensate for such aberrations. Embodiments of the invention are notlimited a single plano-convex or aspherical lens. The invention invarious embodiments may use any lens well known in the art. The systemmay further comprise means for adjusting the distance of the radialoffset. The lens support may also comprise an opaque disc which allowsthe laser beam to pass only through the lens. The system may furthercomprise a driver which is adapted to rotate the support about the axisat a rate in the range from 1 rotation per second to 100 rotations persecond. Some embodiment also further comprises a means for adjusting thedistance of the radial offset.

In the same fashion as the method described above the system embodimentcomprises a mirror for deflecting the focused beam from the focusinglens in a lateral direction relative to the axial direction. Typicallythe mirror is generally oriented at 45° relative to the axial directionand preferably reflects light at the wavelength of the laser beam butallows visible light to pass therethrough.

Some embodiments may further comprise a low power light source orientedto direct a light beam along a path coincident with the path of thefemtosecond laser beam, wherein the low power light source can be usedfor aiming the focusing lens. In some embodiments the femtosecond lasersource comprises a femtosecond laser mounted in a free standing cabinet,wherein the system further comprises a support arm having a proximal endattached to the cabinet and a distal end attached to a housing whichholds the focusing lens, the lens support, and the depth control means.Another exemplary aspect of preferred embodiments is that the lenssupport is adapted to be coupled to a microscope, wherein the microscopeis oriented to view the eye tissue to be treated. In any embodiment ofthe invention, the laser treatment system may be mounted or otherwiseincorporated into a surgical microscope. In exemplary embodiments, thelens support of the system may be mounted on a surgical microscope whereits location can be switched between a disengaged and engaged positionunder the microscope.

Yet another aspect of the invention is a phacoemulsfication machine.This aspect comprises at least the following elements: a housing, a pumpand controller located within the housing for delivering a fluid to aneye capsule to emulsify a lens within the capsule, a femtosecond laserlocated within the housing, a support arm having a proximal end securedto the housing and distal end postionable in a space surrounding thehousing, and a laser delivery system secured to the distal end of thesupport arm wherein the laser delivery system is adapted to deliverfocused laser light from the femtosecond laser to the eye capsule.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 shows an overview of the laser delivery system.

FIG. 2 shows a more close up view of the laser delivery system.

FIG. 3 shows a different angle close up of the laser deliver system.

FIG. 4 shows another version of the delivery system

FIG. 5 shows a detailed view of the optics unit.

FIG. 6 shows a detailed view of the main treatment laser.

FIG. 7 shows a the focused beam entering the eye.

FIG. 8 shows the treatment laser beam intensity profile.

FIG. 9 shows a further embodiment of the laser delivery system.

FIG. 10 shows another embodiment of the laser delivery system.

FIG. 11 shows another embodiment with a general beam expander.

FIG. 12 Illustrates the effect of a slightly more diverging collimationangle of the aiming laser beam relative to that of the treatment laserbeam.

FIG. 13 Illustrates the effect of a slightly more converging collimationangle of the aiming laser beam relative to that of the treatment laserbeam.

FIG. 15 shows the delivery system unit integrated with a standardsurgical microscope

FIG. 16 shows the delivery system unit integrated into a typicalphacoemulsification machine.

FIG. 17 shows a custom contact lens that reduces aberrations

FIG. 18 shows a further embodiment of the custom contact lens

FIG. 19 shows a different view of the a custom contact lens.

DETAILED DESCRIPTION OF THE INVENTION

The invention described relates to techniques apparatus, and systems forlaser eye surgery or laser assisted eye surgery. Specifically describedherein are methods and systems for delivering a focused femtosecondlaser beam into the eye of a patient.

An exemplary embodiment of the invention is shown in FIG. 1. FIG. 1shows a system overview of the laser delivery system optics (104)integrated into a typical ophthalmic surgical microscope 103. Thedelivery system optics unit 104 connects to the laser engine 101 that isplaced here next to the microscope stand through an articulating arm 102that allows propagation of a laser beam. The patient 100 lays in astandard position typical for cataract surgery. The overview iscompleted by illustrating a typical size phacoemulsification machine 105close to the surgical microscope. A closer view of this exemplaryembodiment is shown in FIG. 2. This view shows the right eye beingtreated. The left eye is treated by moving the delivery system 104 ontothe other side of the microscope 103. In this configuration thearticulating arm 102 will simply move further back over the laser box101. The final 45 degree laser mirror 122 is coated to only reflect thelaser wavelength down into the eye. Its coating makes it mostlytransmissive for visible wavelengths, so that the surgical microscope103 view is maintained through this mirror without any significantdistortions. The mounting of the optics until 104 is adjusted such thatthe center of the 45 degree mirror 122 fall into the central opticalaxis of the microscope 103. The optics unit 104 moves together with themicroscope head. It allows for some clearance over the patients eye 121and away from the patients nose. FIG. 3 shows a different angle view ofthe 45 degree mirror 122. It illustrates a typical spacing above thepatient's eye and illustrates a highly focused laser beam 140 enteringthe eye.

FIG. 4 shows another version of the delivery system were the final 45degree mirror is mounted in a gimbal mount that allows the mirror to beactuated around the x-axis and y-axis. This actuation is preferably donewith galvo scanners 160 and 161 or other rotational motors. Thisactuated 45 degree mirror allows scanning of the laser beam 140 in a2-dimensional plane parallel to the iris plane of the eye. Together withthe rotating lens 182 and the z-scanning lenses 244 the actuated mirrorsignificantly expands the scanning ability of the system withoutintroducing any significant beam aberrations.

FIG. 5 shows a detailed view of the optics unit 104. A collimated laserbeam 188 enters the unit on the right. The laser beam 188 propagatesthrough a beam expander consisting of 2 lenses 187 and 185. These 2lenses create in this preferred version a Galileo telescope with thefirst lens 187 mounted on a linear motorized drive stage 190. Thiscontrolled movement of lens 190 or alternatively lens 185 parallel tothe laser beam 188 allows the exiting expanded beam 191 to be slightlymore or less converging towards its focus point in the eye. Thisvariation in convergence angle of 191 results in an effective z-scan ofthe laser focus within the eye 121. The focusing lens 182 is mounted ina rotational mount 521, being rotated in a circular way, driven by amotor 123 and a drive mechanism 192. Depending on the treatment laserparameters such as the repetition rate of laser pulses and the desiredtreatment circle speed the rotating speed of lens 182 can be adjustedwith the motor 123. Typical rotational speeds will be between 1 to 100full rotations per second. The rotational mount 521 either mounts thelens with a fixed offset or a manual adjustable offset amount (adjustedbefore the procedure) or a motor driven continuously adjustable offsetamount that can be adjusted either before or during the treatmentprocedure. The mount 521 includes a fixed or automatically adjustablecounterweight to compensate the offset lens mass and maintain fullrotational balance at any time.

FIG. 6 gives another detailed view of the main treatment laser beam paththrough the delivery system unit 104. The treatment beam 188 is shownpropagating through the beam expander lenses 187 and 185 and then beingclipped to a smaller beam size as it propagates through the focusinglens 182 and then is being focused as 191 into the eye via the 45 degreeflat mirror 122.

Even though the here introduced delivery system minimizes beamaberrations by design some remaining aberrations need to be considered.As shown in FIG. 7, when the focused beam 191 enters the eye through thecurved cornea surface interface 196 and to a lesser extend through alleye internal surfaces that the laser propagates, the focusing parametersof the beam are changed. This shifts the focus distance in the verticalaxis to a new distance 195. This shift in focus does not need to becompensated for if a aiming laser beam pattern is used to target thedesired tissue, since the aiming laser beam is always collinear to thetreatment beam and will experience almost the same shift. Thereforeadjusting the target area with the aiming beam

Furthermore if the beam centerline 197 has an offset 194 to thecenterline of the eye 198 the beam focus experiences a slight shift 193towards the center of the eye. The amount of shift depends on how deepthe focus is placed within the eye 195 and at what radial distance 194from the centerline 198 the beam enters the eye. This shift can beeasily measured and calculated for any given offset number and cantherefore be compensated for if desired. The shift furthermore effectsthe aiming beam in the almost same amount (except for a small wavelengthdependency) and is therefore already anticipated and included in thevisual alignment of the target zone.

The radial offset 194 creates spherical and other higher orderaberrations that reduce the beam quality and therefore enlarge theachievable spot size inside the eye. The aberrations can however bemeasured and calculated for any given offset and can effectively beeliminated by a custom shaped focusing lens 182 that pre compensates forthe aberrations. For example, if a circular capsulotomy scan pattern isperformed with a cutting diameter of 5 mm diameter, then the aberrationsinduced by the corresponding 2.5 mm radial offset 194 can be premeasured and a custom shaped focusing lens 182 can be used to precompensate these aberrations. As the focus moves in a circle inside theeye, the focusing lens rotates accordingly so that the direction of thecustom shape of the lens 182 is always in the correct direction tocompensate the aberrations at any moment during the entire rotation.

Another way to reduce or eliminate these aberrations without the needfor a custom shaped focusing lens 182 is by using a custom contact lensas shown in FIGS. 17 and 18. These lenses are placed on the eye andprovide a flat upper surface that essentially eliminates the abovedescribed aberrations and shifts. These contact lenses can be fullpatient interfaces connecting the eye to the delivery system or arepreferably designed to not connect to the delivery system unit and donot change any of the above described contactless design systems andmethods.

FIG. 8 illustrates the treatment laser beam intensity profile 523 as itoverfills the rotating focusing lens 182 mounted inside an offset mount521. The laser beam center line 186 is also the rotational axis of thelens mount. To achieve sufficient beam homogeneousness over the entirefocusing lens area and during the entire lens rotation an adequateoverfilling ratio is selected. In the here shown overfill selection theentire lens through all of its rotational positions stays within a 80%intensity beam width 524 portion 522 of the Gaussian laser beam 523.Limiting the lens position to that central laser zone creates nearlyuniform intensity profile since this top intensity curve 522 section isrelatively flat. Depending on how uniform the intensity profile isdesired, the beam overfilling amount can be increased or reduced.Depending on the laser beam coherence quality, If the laser beam startsout more like a flat top profile versus a perfect Gaussian profile thenless overfilling is required to achieve the same homogeneous intensityprofile. The focusing beam 191 shows the portion of the incoming laserbeam that gets focused onto the target plane. 520 illustrates thescanned focused circle that is achieved through the rotating lens. Thelens offset can be adjustable and is here shown by the distance betweenthe central lens axis 181 and the central system and incoming beam axis186. More typical laser beam width definitions such as full width halfmaximum FWHM 525 and 1/e² diameter 526 are also illustrated as areference here.

FIG. 9 illustrates further details and embodiments of the here disclosedlaser delivery system. The rotating lens 182 is shown here in itsmomentary lowest position. The offset can be seen between the centralsystem axis 248 and the central lens axis 249. This offset results herein the laser focus being placed inside the lower eye 121 on the rightside. The 45 degree mirror 122 is here shown as optional. It is usedwhen the delivery system is integrated under a microscope 103 with thecentral viewing axis 189 going through the center of the mirror 122. Thedelivery system can also be operated in a straight way without a 45degree mirror. This version can be used in an office setting where thedelivery system is integrated with a slit lamp. Furthermore a optionalpatient interface 240 is illustrated that creates a hard dockingconnection between the eye and the delivery system. The preferredembodiment uses no hard connected patient interface and there is nocontact between the delivery system and the eye. To reduce aberrationsand to improve eye fixation several custom eye contact lenses aredescribed later. They are only connected to the eye and do not make anycontact to the delivery system and are therefore still considered acontactless approach.

FIG. 10 shows further embodiments and details of the delivery system.Above the 45 degree mirror 122 is another optional 45 degree mirror 501.It is also transmitting most of the visible wavelengths so that themicroscope 103 view 189 is no much affected by it. Its purpose is toreflect a eye fixation light beam 503 coming from the illumination gridunit 504. The delivery system is adjusted over the eye 121 so that theeye fixation light beam 503 becomes the central axis beam through thepatient's eye 121. The patient will fixate his eye by keeping this lightin his central view either during docking if a patient interface 240 isused or during the entire procedure if no patient interface is used. Theillumination grid unit 504 further produces light pattern beams 502 thatcreate a visible grid pattern on the outer or inner surfaces of the eye.These grid patterns are used by the surgeon to center the eye ortreatment zone(s).

The aiming beam module 243 includes a low power aiming beam laser andbeam shaping optics that allow for a fixed or adjustable laser beamdiameter. The size of the aiming beam diameter determines the spotsizeof the aiming beam pattern in the target region of the eye. According toFormula 1, a large aiming beam diameter will result in a large focusingangle and small spot size. This will increase the sensitivity andresolution in the z-axis adjustment of the microscope connected to thedelivery system unit 104 and allows for a more precise z-plane detectionby focusing the aiming beam pattern (circle) onto a surface interface ofor within the eye. This interface could for example be the top or bottomsurface of the cornea, the anterior or posterior capsule surface, theiris plane or other interfaces. The preferred aiming beam diameter is20% to 80% of the collinear treatment beam diameter.

The aiming beam 247 is collinear overlapped to the treatment laser beam188 through a 45 degree mirror 242 with a dichroic coating. For easierdiagram readability it is here only shown until the mirror 242, but itdoes continue collinear to the treatment beam throughout the entireoptical system. The collimation angle of the aiming beam is adjustedwithin the optic unit 243 such that the focus plane of the aiming beamin the eye is vertically offset to the focus plane of the treatmentlaser beam. This offset can be adjusted in both directions to achieve anup or down focus plane offset in the z-axis.

FIG. 11 shows further embodiments and details of the delivery system.Here the beam expanding unit that was shown in FIG. 008 as a GalileoTelescope with the lenses 244 has now been replaced with a general beamexpanding unit 540 that allows fixed or adjustable (with a zoom lenssystem) expansion factors. The expansion amount can be adjusted fromoverfilling as described in FIG. 007 to under filing the lens 182 shownhere in FIG. 010. The beam diameter 541 exiting the expansion unit 540is here set so small that it always remains within the lens 182 areawhile the lens rotates around the central axis 186 with an offsetillustrated by the central lens axis 181. In this version all of thelaser power is delivered to the target spot and none of the beam isclipped during the rotation of the lens. This smaller beam going throughthe focusing lens 182 results in a larger spot size compared to a fullyor overfilled lens 182. It does however not change the position of thefocus inside the eye. This configuration is chosen when the prioritylays in delivering more laser power to the eye versus achieving aminimum spot size. By using an adjustable zoom beam expander unit 540,the spot size and beam delivery power (if clipping occurs) can beadjusted before the laser treatment or during the laser treatmentprocedure. The resulting change in beam diameter 541 before the focusinglens 182 results in a changing focusing angle θ and according to FormulaI in a changing focus size diameter 2×ω0.

FIG. 12 illustrates the effect of a slightly more diverging collimationangle of the aiming laser beam 247 relative to the treatment laser beam188. Both beams go through the same focusing lens 182. This results in afocus plane shift between the two lasers. The treatment beam 188 isfocused in spot 584, which is closer to the lens than the focus spot 583of the aiming beam 247. The aiming beam focal plane is shifted furtheraway from the focusing lens 182 by the amount of delta Z 582.

FIG. 13 illustrates the effect of a slightly more converging collimationangle of the aiming laser beam 247 relative to the treatment laser beam188. Both beams go through the same focusing lens 182. This results in afocus plane shift between the two lasers. The treatment beam 188 isfocused in spot 584, which is further from the lens than the focus spot602 of the aiming beam 247. The aiming beam focal plane is shiftedcloser to the focusing lens 182 by the amount of delta Z 601.

This design feature is used to align the delivery system with the helpof a aiming beam pattern or circle and then fire the treatment laserstarting above (as illustrated in FIG. 011 or below the aligned plane asshown here in FIG. 012. For example to make a capsulotomy incision withthis delivery system, the aiming beam circle (created from a staticaiming beam going through the rotating lens 182) is focused onto thesurface of the lens capsule. The treatment laser plane starts shifteddown by (delta Z). The treatment laser is fired and through an upwardz-scan performed with lens 187 the treatment beam is scanned in a upwardspiral, cutting through the capsular bag.

FIG. 14 shows the delivery system unit 104 integrated with a standardsurgical microscope 103 in a disengaged position. This position leavesfull access for the surgeon under the microscope to perform any standardsurgical procedure such as the cataract lens extraction or intraocularlens placement. The delivery system unit is connected to the microscopeusing a swing arm bracket 261 and a mounting adapter 260 placed belowthe main surgical view port 119. The swing arm bracket 261 is here shownin its up position for a right eye treatment. FIG. 15 shows the sameview with the swing arm bracket locked in its lower position. This makesthe system ready for the laser treatment part of the surgery.

The swing arm bracket can be moved during the surgery between the up anddown position in a manual way using optional sterile handles or in apreferred version is motorized and can be switched up and down using asingle foot or hand switch. The lower position that enables the lasertreatment includes a precision referenced stop in all 3 dimensions thatassures calibrated distances and assures alignment of the main opticalmicroscope viewing axis to the axis going centrally through the 45degree mirror 122. The articulating arm 102 allows the delivery systemunit 104 to be moved between around with the microscope in both the upand down position without affecting the laser beam alignment enteringthe delivery system unit 104.

FIG. 14 and FIG. 15 show the microscope integration for a right eye. Theleft eye configuration can be equally achieved by bringing the mountingbracket 261 to the other side of the microscope head 103. This can beeither done manually before the surgery or with a motorized mechanismincorporated in the mounting adapter 260.

FIG. 16 FIG. 017 shows another version were a compact laser engineversion 620 is integrated into a typical phaco emulsification machine asa sub module 620. The articulating arm 102 is now exiting the phacomachine together with all other power and control lines that arepreferably routed along the articulating arm 102. This integrated designallows for a most efficient surgical setup where all aspects of thetypical cataract surgery can be controlled by one machine. The laserdelivery system unit 104 to microscope 103 integration is identical toFIGS. 014 and 015.

FIG. 17 shows a custom contact lens that reduces aberrations andincreases eye fixation while still being contactless in regard to thedelivery system. It is designed to be used in a position where thepatient lays on his back and the central eye axis is parallel togravity. The aberrations are minimized by using a high qualitytransparent material 404 with a flat top surface 403. The lens is placedalong the limbus 230 of the eye. An optional suction ring 402 can beincorporated to increase the connection stability of the contact lens tothe eye. This design causes no cornea applanation or significant intraocular pressure rise due to the liquid inner cell 410.

After the lens has been placed on the eye the inner cell 410 is filled400 with water or similar liquid through an opening 401 on the lower endof the contact lens. Due to the slope 405 of the inner top surface anyremaining air bubbles will be pushed out 409 through an exit hole 408 onthe upper end of the contact lens. The water is injected until all airhas left the space 410.

Due to this liquid interface a very good refractive index matching isachieved between the material on the top of the contact interface, theliquid in space 410 and the cornea 223. This creates a low aberrationentry path of a highly focused laser beam into the eye.

By using this contact lens the rotating focusing lens in the deliverysystem can be simplified to a standard plane-convex single lens and thelaser beam can be scanned with very low aberrations throughout theentire eye.

FIG. 18 shows another custom contact lens that reduces aberrations andincreases eye fixation while still being contactless in regard to thedelivery system. This design is comprised of a clear material 220 thatis either solid and curved to match the radius of curvature of thecornea 223 or is filled with a clear liquid and then stabilized with aflat glass plate 221. In either case the top surface 221 is flat andtherefore minimizes aberrations. The lens includes an outer flange 225that extends over the sclera 226 while maintaining a small gap 231. Thisgap assures that a good cornea connection of a solid version material220 is achieved. When a liquid material 220 is used, the gap is thenautomatically closed and seals the liquid in.

The flange 225 includes an angled slope surface 224 that is designed tointerface with a speculum such that the contact lens is slightly pusheddownwards towards the eye. This is illustrated in FIG. 19.

The speculum 203 is holding the eye open and in the same time pushes thecontact lens towards the eye through a contact of the speculum wire 202or blade with the sloped surface 224. The amount of down force can beadjusted by the amount of speculum opening and by the design angle ofthe slope 224. This contact lens creates stable eye fixation andminimizes laser beam aberrations for laser access of the entire eye.

1. A method for forming an incision in eye tissue, said method comprising: directing a femtosecond laser beam in an axial direction; moving a lens over a path within the beam, wherein a plane of the lens remains perpendicular to the axial direction and the lens focuses an incident portion of the laser beam to a spot within the eye tissue, wherein the spot has a size which will photo-disrupt tissue along a two dimensional path determined by the path of the lens; and controlling a depth of focus of the laser spot to create a three dimensional treatment area within the eye tissue.
 2. A method as in claim 1, wherein the lens is moved over a circular path to create a cylindrical incision in the eye tissue.
 3. A method as in claim 2, wherein the eye tissue comprises a lens capsule.
 4. A method as in claim 1, further comprising blocking portions of the femtosecond laser beam which are not incident on the lens.
 5. A method as in claim 1, wherein moving the lens comprises rotating a lens support about an axis parallel to the axial direction of the beam axis, wherein a center of the lens is radially offset from the support axis.
 6. A method as in claim 5, wherein the lens support is an opaque disc which allows the laser beam to pass only through the lens.
 7. A method as in claim 5, wherein the lens support is rotated at a rate in the range from 1 rotation per second to 100 rotations per second.
 8. A method as in claim 5, further comprising adjusting a distance of the radial offset.
 9. A method as in claim 1, wherein controlling a depth of focus comprises adjusting expansion of the beam prior to the beam striking the lens.
 10. A method as in claim 9, wherein the expansion is adjusted by controlling the distance between a pair of lenses in a Galileo telescope.
 11. A method as in claim 9, wherein the expansion is adjusted by a beam expander.
 12. A method as in claim 1, further comprising aiming the lens prior to directing the femtosecond laser beam through the lens.
 13. A method as in claim 12, wherein aiming comprises directing a low power light through the moving lens so that a visible pattern is projected on the tissue, wherein the orientation of the lens can be adjusted until the visible pattern is located at a desired incision site.
 14. A method as in claim 1, further comprising deflecting the focused beam from the moving lens to follow a path at an angle relative to the axial direction.
 15. A method as in claim 14, wherein deflecting comprises placing a partially reflective mirror in the focused beam to allow viewing of the eye tissue through the mirror.
 16. A method as in claim 15, wherein the mirror is oriented at 45° relative to the axial direction.
 17. A system for forming a three dimensional treatment zone in eye tissue, said system comprising: a femtosecond laser source which directs a beam in an axial direction; a focusing lens; and a lens support which holds the focusing lens in a plane perpendicular to the axial direction and which moves the lens over a two dimensional path in the perpendicular plane, wherein the focusing lens focuses a portion of the beam incident on the lens to a spot size selected to disrupt eye tissue; and means for controlling a depth of focus of the laser spot to create a three dimensional incision within the eye tissue.
 18. A system as in claim 17, wherein the femtosecond laser source comprises: a laser which produces a collimated femtosecond laser beam; and means for expanding the beam prior to the beam reaching the focusing lens.
 19. A system as in claim 18, wherein the beam expanding means comprises a Galileo telescope.
 20. A system as in claim 18, wherein the beam expanding means comprises a beam expander.
 21. A system as in claim 18, wherein the beam expanding means is adjustable to control the depth of focus of the laser spot with the eye tissue.
 22. A system as in claim 17, wherein the focusing lens is a single aspherical lens that precompensates beam aberrations that the laser beam experiences as it propagates into the eye.
 23. A system as in claim 17, wherein the lens support is mounted to rotate about an axis parallel to the axial direction and wherein a center of the lens is radially offset from the axis.
 24. A system as in claim 23, wherein the lens support comprises an opaque disc which allows the laser beam to pass only through the lens.
 25. A system as in claim 23, further comprising a driver which is adapted to rotate the support about the axis at a rate in the range from 1 rotation per second to 100 rotations per second.
 26. A system as in claim 23, further comprising means for adjusting the distance of the radial offset.
 27. A system as in claim 17, further comprising a mirror for deflecting the focused beam from the focusing lens in a lateral direction relative to the axial direction.
 28. A system as in claim 27, wherein the mirror is oriented at 45° relative to the axial direction.
 29. A system as in claim 27, wherein the mirror preferentially reflects light at the wavelength of the laser beam but allows visible light to pass therethrough.
 30. A system as in claim 17, further comprising a low power light source oriented to direct a light beam along a path coincident with the path of the femtosecond laser beam, wherein the low power light source can be used for aiming the focusing lens.
 31. A system as in claim 17, wherein the femtosecond laser source comprises a femtosecond laser mounted in a free standing cabinet, wherein the system further comprises a support arm having a proximal end attached to the cabinet and a distal end attached to a housing which holds the focusing lens, the lens support, and the depth control means.
 32. A system as in claim 17, wherein the lens support is adapted to be coupled to a microscope, wherein the microscope is oriented to view the eye tissue to be treated.
 33. A system as in claim 32, wherein the lens support is mounted on a microscope where its location can be switched between a disengaged an an engaged position under the microscope.
 34. A phacoemulsification machine comprising: a housing; a pump and controller located within the housing for delivering a fluid to an eye capsule to emulsify a lens within the capsule; a femtosecond laser located within the housing; a support arm having a proximal end secured to the housing and a distal end positionable in a space surrounding the housing; and a laser delivery system secured to the distal end of the support arm, wherein the laser delivery system is adapted to deliver focus laser light from the femtosecond laser to the eye capsule. 